38 Storage Management with DB2 for OS/390
5.3 SMS Classes
The storage administrator usesI SMF to create an ACSroutine for each of the
three types of classes and one to assign the Storage Groups. These routines,
used together with the Data Class, Storage Class, Management Class, Storage
Group definitions, and the base configuration,define an installation’s SMS
configuration.
Figure 13 on page 38s howsthe relationship of each of the four constructs which
make up theSMS ACS routine environment. The following sections describe
each of theclasses in more detail.
Figure 13. SMS Construct Relationship

5.3.1 Data Class

5.3.1.1 Description
Formerly,when allocating new data sets, users were required to specify a full set
of attributes.Even for multiple allocations, repetitive coding was required. With
the introduction of SMS,this process is now simplified, and also helps to enforce
standards by use of the Data Class.
A Data Class is a named listof data set allocation and space attributesthat SMS
assigns to a data set when it isc reated.It contains associated default values set
bythe storage administrator.Data Classes can be assigned implicitly through the
ACS routinesor explicitly using the following:
• JCL statement. The user only need specify the relevant Data Class keyword
such as DATACLAS=DCLIB
• TSO/E ALLOCATE command DATACLAS(DCLIB)
• IDCAMS ALLOCATE and DEFINE commands
• ISPF/PDF Data set allocation panel
When specified, theData Class allocates a data set in a single operation. Any
disk data setcan be allocated with a Data Class whether managed by SMS or
not. Tapedata sets cannot be allocated with Data Classes.
Data
Class
SMS Construct Relationship
Management
Class
Storage
Group
Storage
Class
Dataset
Organization Performance
Availability Location